The present invention relates to an optical article having anti-reflective and anti-glare properties and also having self-healing properties and scuff resistance imparted by a thin, multi-layered film. The optical article of the present invention thus is effective in reducing glare.
The problem that is solved by this invention is one of glare or reflection. Many organizations use outdoor monitors to convey information or conduct business with visitors and customers. Also, banks, for example, use Automatic Teller Machines (ATMs) to conduct business with their customers. In many instances, a customer cannot clearly see the monitor screen because of a reflection or glare. The reflection or glare may be caused by, for example, sun light or reflected light from, for example, concrete. The present inventors have developed a highly effective product in reducing the problem of glare and/or reflection.
Sometimes glare is distinguished from a reflection as being more dull, usually from a matte finish (as opposed to a gloss finish). Since the optical article of the present invention greatly reduces both glare and reflection, for the purposes of this Specification, no distinction between the two is made.
Various methods of reducing glare and reflection have been proposed. For example, linear and circular polarizers are well known to those skilled in the art.
U.S. Pat. Nos. 2,173,304; 2,306,108 and 2,255,940 disclose light polarizing material.
U.S. Pat. No. 5,326,968 discloses a photoelectric sensor adapted for use in specific applications which requires the additional attachment of a circular polarizer.
U.S. Pat. No. 5,015,072 discloses a glare-reducing shield usable with a touch-screen display that includes a shade positioned above the display and a circular polarizer mounted within the shade and above the touch-screen display.
U.S. Pat. No. 4,278,736 discloses a contrast enhancement filter having a sheet-like circular polarizer disposed between two glass substrates secured by a polyvinyl butyral adhesive. The contrast enhancement filter of U.S. ""736 is typically used in conjunction with a display tube of a conventional type or other display such as a gas plasma or light emitting diode (L.E.D.) which has a transparent face plate in one wall thereof.
U.S. Pat. No. 4,747,674 also discloses a contrast enhancement filter comprising a fluorinated polymer, an indium tin oxide (antistatic) layer, and a circular polarizer. Examples of useful fluorinated polymers include vinylidene fluoride homopolymers and copolymers, perfluorinated polyolefins and fluorinated acrylates and methacrylates. The contrast enhancement filter of U.S. ""674 is disclosed as being useful as a means for reducing specular glare from the surface of cathode ray tubes, computer display screens and the like.
U.S. Pat. No. 5,449,558 discloses an optical article comprising a layer of a resin having self-healing properties and scuff resistance, and an anti-reflection layer of a non-crystalline fluorine-containing polymer. Example 1 describes the use of the optical article in combination with a linear polarizer.
The present invention relates to an optical article that comprises a layer of a transparent resin having a self-healing property; an antireflection layer; and a circular polarizer. Further, the optical article of the present invention is also soil and stain resistant. Thus, soil and stains from, for example, fingerprints and graffiti may be easily removed. Preferably, the optical article of the present invention comprises a first layer of a transparent resin having a self-healing property; an antireflection layer consisting essentially of a non-crystalline fluorine-containing polymer disposed underneath the first layer; and a circular polarizer disposed underneath the antireflection layer. The elasticity of the first layer helps provide for the self-healing property and thus helps provide the scratch and scuff resistance of the optical article of the present invention.
The optical article of the present invention provides anti-reflective and glare reduction properties by means of a non-crystalline fluorine-containing polymer and is used with a circular polarizer. The optical article is then placed in front of, for example, a viewable screen. When a protective screen (i.e., a prior art protective screen) is installed in front of a display screen, about 5% of the incoming light is reflected back to the viewer from the first surface (i.e., the protective screen). The remaining 95% pass through the first surface and about 5% of the remaining light is reflected back from the second surface (i.e., the display screen) through the protection material. Thus, about 10% of the light is reflected and perceived as glare to the viewer.
The non-crystalline fluorine-containing polymer reduces the first surface reflection from about 5% to about 0.5%. The circular polarizer reduces the reflected light from the second surface by about 94-100% (depending on the wavelength of the light). The combined glare reduction of the optical article of the present invention thus reduces the glare of the incoming light by about 93.5-100% as compared to a standard monitor having no antireflection film depending on the wavelength of the incoming light. The optical article of the present invention is also durable, scratch resistant, has self healing properties and improves contrast and brightness.
Preferably, the optical article of the present invention is placed over, for example, a monitor such as computer screen, television, bank ATM machine, outdoor monitor, indoor monitor or an electronic navigation screen. The optical article of the present invention reduces glare without adversely affecting the image as seen by the operator.
Further, the optical article of the present invention is cost-effective and, as such, can be used in such applications as for example, storefront windows.